1. Technical Field
The present invention relates to a flow path component which is used in a liquid discharge head such as an ink jet type recording head, and a liquid discharge apparatus, particularly, to a flow path component which is formed from a silicon substrate, a liquid discharge head, and a liquid discharge apparatus.
2. Related Art
A liquid discharge apparatus is an apparatus which includes a liquid discharge head, and discharges (ejects) various types of liquids from the discharge head. As such a liquid discharge apparatus, for example, there is an image recording apparatus such as an ink jet type printer or an ink jet type plotter, but recently, the liquid discharge apparatus is applied to various types of manufacturing apparatuses by using a feature of being able to accurately land the liquid of a very small amount at a predetermined position. For example, the liquid discharge apparatus is applied to a display manufacturing apparatus which manufactures a color filter such as a liquid crystal display, an electrode forming apparatus which forms an electrode such as an organic electro luminescence (EL) display or a field emission display (FED), or a chip manufacturing apparatus which manufactures a biochip (biotip). Therefore, a liquid ink is discharged in a recording head for the image recording apparatus, and a solution of each color material such as red (R), green (G) or blue (B) is discharged in a color material discharge head for the display manufacturing apparatus. Moreover, a liquid electrode material is discharged in an electrode material discharge head for the electrode forming apparatus, and a solution of a bio-organic matter is discharged in a bio-organic matter discharge head for the chip manufacturing apparatus.
In such a liquid discharge head, for example, a nozzle plate where a plurality of nozzles are installed, a substrate where a plurality of hollow portions to be a pressure chamber communicating with the respective nozzles are formed, a substrate where a flow path hollow portion to be a common liquid chamber (referred to as reservoir or manifold) in which the liquid being common to the respective pressure chambers is accumulated is formed, a plurality of piezoelectric elements (one type of actuators) which are respectively arranged correlating with the respective pressure chambers and the like are included. In such a configuration, since a flow path and the like can be formed by an etching highly accurately, a silicon substrate (silicon single crystal substrate) is adopted, as a material of the substrate which forms the flow path (for example, see JP-A-2014-037133).
In the configuration which is disclosed in JP-A-2014-037133, as illustrated FIG. 12, among a communication substrate 64 where the flow path hollow portion of the common liquid chamber is formed, a hollow is made by the etching in the middle of a substrate thickness direction toward an upper plane side from a lower plane of the communication substrate 64, and thereby, a hollow portion (referred to as liquid chamber hollow portion, hereinafter) 65 being a portion of the common liquid chamber is formed. Moreover, in the communication substrate 64, an individual communication opening 66 which penetrates the upper plane of the communication substrate 64 from the common liquid chamber is formed, in order that the common liquid chamber individually communicates with the respective pressure chambers. The individual communication opening 66 functions as a flow path of individually supplying the ink to the pressure chamber from the common liquid chamber side. In addition thereto, the individual communication opening 66 is a portion relating to discharge efficiency at the time of discharging the ink from the nozzle by driving the actuator. Hence, a flow path sectional area (hole diameter) or a flow path length is designed, so that flow path resistance, inertance or the like is suitable in the individual communication opening 66. Since a hole diameter X of the individual communication opening 66 is determined to a degree being the minimum value depending on a processing method, in general, a full length L′ of the individual communication opening 66 is mainly adjusted, so that the inertance or the like becomes the suitable value after the hole diameter X is determined to be fixed.
However, if the length L′ of the individual communication opening 66 is set to be suitable, since a depth D of the liquid chamber hollow portion 65 tends to be shallow along therewith, that is, since the flow path sectional area of the liquid chamber hollow portion 65 becomes small, the flow path resistance becomes significant in the liquid chamber hollow portion 65, and hereby, there is a tendency that a pressure loss is increased. In contrast, when the depth D of the liquid chamber hollow portion 65 is secured in order to suppress pressure loss, the length L′ of the individual communication opening 66 is insufficient.